Lecture 2 Unit I identify and describe the set of processes that allow a linear sequence of information contained in DNA to direct the embryonic development of a complex Study Guide for BSC 2011 UNIT 1 EXAM multicellular eukaryotic organism from a single cell 1 Know that DNA is organized into structures called chromosomes a Chromosomes packed with DNA molecules maintained by proteins In eukaryotic cells the chromosome is very long and linear 2 Be able to explain the significance of the coiling of chromatin a The entire complex of DNA and proteins that is the building material of chromosomes is referred to as chromatin which varies in degree of condensation during different processes of cell division 3 Be able to describe the multiple functions of cell division a 1 The reproduction of an entire unicellular organism 2 the growth and repair of tissues in multicellular animals and 3 the formation of gametes eggs and sperm for sexual reproduction in multicellular animals The process of mitosis produces identical cells for the first two functions listed above the process of meiosis forms gametes 4 Know that cell division results in genetically identical daughter cells 5 Be able to describe the structure of a eukaryotic chromosome a The DNA of eukaryotic animals is packaged into chromosomes Chromosomes come in pairs they are almost the same but with slight variations Humans have forty six chromosomes or twenty three pairs When DNA is replicated before the cell divides each chromosome has two identical copies of DNA called sister chromatids 6 Be able to diagram the cell cycle indicating the timing of all processes a Interphase 90 of the cell cycles Not tightly bound during interphase i G1 cell growth 5 6 hrs ii S duplication of chromosomes 10 12 hrs 1 Still one chromosome creates two sister chromatids which connect at centromere iii G2 completes preparation for cell division 4 6 hrs iv Mitotic cell divides 1 hr 7 Know that separation of sister chromatids occurs in Mitosis 8 Know the major stages of Mitosis and what happens in each a Mitosis the major division of genetic material in the NUCLEUS b Prophase c Prometaphase d Metaphase e Anaphase f Telophase SEE ATTACHED MITOSIS DOCUMENT 9 Be able to explain one potential evolutionary pathway leading to mitosis a Dinoflagellates diatoms some yeasts has nuclear division where nuclear envelope remains intact The fact that some proteins involved in binary fission process seen in bacteria are related to eukaryotic proteins that function in mitosis 10 Be able to explain the experiment demonstrating that the spindle moves chromatids through tubule shortening a Labeled microtubules in kidney cell w yellow dye Results Chromosomes correlated w kinetochore microtubules shortening at kinetochore ends not spindle pole ends Stained sections didn t move but centromeres got closer 11 Be able to explain the control of mitosis through CdK and cyclin a Regulatory molecules are protein kinases and cylcins Kinases are active when attached to cyclins which are called Cdks cyclin dependent kinases b Activity of Cdks rise and fall with changes in concentration of cyclin c Cyclin rises during S and G2 and falls abruptly in M phase d Anaphase switches itself off by initiation destruction of cyclin 12 Know that cancer is the result of a failure of control of the cell cycle Terminology Histone Small protein that plays a key role in chromatin structure 1st packing level chromatin complex of DNA proteins that is the building material of chromosomes nucleosome sister chromatid Joined copies of the original duplicated chromosome centromere Region that joins sister chromatids genome Genetic material of organism somatic cell all body cells except reproductive gamete sperm cells and egg cells has the number of chromosomes as somatic cells fuse to form zygote mitosis 9 Division of genetic material in nucleus of eukaryotes is divided into 5 phases prophase prometaphase metaphase anaphase and telophase meiosis G1 G2 and S phases cytokinesis Reading Chapter 16 320 322 review Chapter 12 1 Know that a transcription factor is a molecule that can either stimulate or inhibit the expression transcription of a gene 2 Know that a proto oncogene is a gene whose product stimulates growth i e the cell cycle 3 Be able to explain the three mechanisms through which a proto oncogene becomes an oncogene a Translocation or transposition gene moves to new locus under new controls b Gene amplification multiple copes of the gene c Point mutation either in the promoter or enhancer that controls the proto oncogene or in the coding sequence of the proto oncogene changing it to a protein that is more active or more resistant to degradation Lecture 3 4 Know that ras is the product of a proto oncogene and be able to explain how its mutation can lead to cancer a Rat sarcoma a G protein that relays a signal from growth factor to a cascade The cellular response is the synthesis of a protein that stimulates the cell cycle b Not normally triggered w out growth factor but when there is a mutation it can precede w out GF and an increase in cell division 5 Know that p 53 is a tumor suppressor gene and be able to explain how a mutation that inactivates it can lead to cancer a Tumor suppressor genes help prevent uncontrolled cell growth b P 53 encodes for TF that promotes synthesis of cell inhibiting proteins c A mutation that knocks out the p 53 gene like a hyperactive ras protein can lead to excessive cell growth and cancer Reading Section 18 5 page 360 Chapter 15 review as needed 1 Be able to explain what gene expression means transcription and translation of genes a The regulation of transcription and translation results in the production of specific proteins and therefore control gene expression 2 Be able to explain that the differences in phenotype structure and function of cells with identical genomes is due to differences in gene expression a Differential gene expression is the expression of different genes by cells with the same genome b Transcription factors must locate the right genes at the right time c Selective genes are turned on and off in the cells 3 Be able to explain that cell differentiation is largely a result of expression a Gene expression is controlled at transcription regulation at this stage occurs in response to signals coming from outside the cell 4 Be able to explain that gene expression can either be induced or repressed and the situations in which that occurs Lecture 4 Gene
View Full Document
Unlocking...